Vapor generating and superheating unit



June 28, 1960 DE CARR c. BRADDY 2,942,536

VAPOR GENERATING AND SUPERHEATING UNIT 2 Sheets-Sheet 2 Filed Dec. 2, 1957 FIG.3

INVENTOR.

De Carr C. Braddy ATTORNEY 2,942,586 r "VAPOR GENERATING AND SUPERHEATING :De Can- C. Braddy, Jamaica Estates, N.Y., assignor to I The Babcock & Wilcox Company, New York, N.Y., a

corporation of New Jersey Filed Dec. 2, 1957, Ser. No. 700,070

11 Claims. (Cl. 122-476) This invention relates to the construction and operation of binary elastic fluid power plants and-more particularly to improvements in the construction and operation of a fluid heating unit especially adapted for the generation of highly superheated high pressure vapor and high temperature high pressure gases for use in the production of power by a binary elastic fluid power plant;

In accordance with the invention, the fluid heating unit is of the supercharged type and is particularly adapted for use in a power plant including a vapor or steam turbine, a gas turbine, and an air compressor driven by the gas turbine. The term supercharged as used herein means a combustion process wherein the pres-sure of the gases generated'in the fluid heating unit is of such magmtude that useful work maybe done by these gasesafter leaving the fluid heating unit through expansion in a gas turbine to essentially atmospheric pressure.- The l in-' yention provides for a fluid heating unit comprising an upright vessel and an upright combustion chamber arranged to receive fuel and high pressure combustionair and centrally disposed within the upright vessel. A substantially circular wall including upwardly extending fluid heating tubes is disposed between the combustion chamvzber and the upright vessel and cooperates withthe eom- Ebustion chamber to form a gas pass thereabout occupied .by fluid heating surface and communicating with the combustion chamber. The circular wall also cooperates with the upright vessel to define a space which is maintained under an air pressure at least equal to the gas pressure in the combustion chamber to counter-balance the outward thrust of the heating gases exerted'on the inside of boundary walls of the combustion chamber and the gas pass. The combustion chamber and gas pass are constructed and arranged so that the heating gases generated in the combustion chamber whirl upwardly therethrough to the gas pass, then flow through thegas pass and over the fluidheating surface disposed therein to the gas turbine. The construction and arrangement of the fluid heating unit of the invention provides a higher efliciency when incorporated in a combined gas turbinevapor turbine power plant than the base steam or gasturbine plants individually; provides a compact installation of reduced size or weight as compared to a conventional unit, largely due to higher heat transfer rates resulting from high gas density in the unit; minimizes the need for lateral steel supports for the boundarywalls of the gas pass and the combustion chamber due to the relatively small pressure ditferential between the inside and the outside of these boundary walls; prevents blasting'or leakage of heating gases through the boundary walls of the combustion chamber or the gas pass; and permits use of relatively simple fluid heating tube arrangements.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification.

.. For a better understanding of theinvention, its operating advantages and specific objects attained by its use, reference'should be had to the accompanying drawings and for central station use.

descriptive matter in which I have illustrated and described a preferred form of myinvention.

Of the'drawings: i Fig. l is a partly diagrammatic sectional elevation of a supercharged steam generating and superheating unit constructed and operable in accordance with the invention;

Fig. 2 is a plan view taken along line 2-2 of Fig. 1; Fig. 3 is a plan view taken along line 3-3 of Fig. 1; Fig. 4 is a sectional elevation of the superheater taken along line 4-4 of Fig. 2; and I Fig. 5 is a diagrammatic representation of the flow paths of the vaporizable fluid, the heating gases and the air in the binary fluid power plant with which the fluid heating unit pf Figs. 1-4 is associated.

In the drawings the invention has been illustrated as embodied in a binary elastic fluid power plant intended The particular power plant illustrated has a net combined output of 57,700 kw., with the steam turbine supplying 39,400 kw. and the gas turbine 18,300 kw., which represents 32 percent of the plant rating. The bottom-supported supercharged natural circulation fluid heating or steam generating unit is designed on natural gas firing for a maximum continuous steam output of 285,000 lbs. of steam per hour at a pressure of 1265'p.s.i. and a total temperature of 950 F. at t e superheater outlet, and a maximum continuous gasdischarge from the steam generating unit to the gas turbine of 450,000 lbs. of gas per hour at a temperature of 1450 F. and a pressure of p.s.i.a.

circulation and-for firing by a gaseous fuel, it will be understood'that the fluid heating unit illustrated may also arranged to deliver steam to a vapor or steam turbine 18,

while passing high temperature high pressure gases to the gas turbine 12. The vapor turbine 18 drives an electric generator 20 and the gas turbine drives an electric generator 22. Heat from the gas turbine exhaust is recovered by passing the gases over the air heater 14 to preheat the compressor discharge air before flowing to the fluid heating unit 16; and over an economizer 24 to partially heat the feedwater for the fluid heating unit.

In accordance with the invention, the fluid heating unit 16 comprises an upright insulation covered metallic vessel 26 of substantially circular cross-section closed. at its upper and lower ends by substantially semi-elliptical walls or heads 28 and 30, respectively, and arrangedwith its major axis substantially verticah An. upright com bustion chamber 30 of substantially circular cross-section is disposed concentrically and substantially symmetrically within the vessel 26, is closed at its opposite ends, land has an axially elongated gas outlet 32 in the circumferential wall thereof. An upright annular gas pass 34, is

disposed about and defined in part by the circumferential wall of the combustion chamber 30, extends along ab out.

three-quarters of the height of the combustion chamber starting from the upper end thereof, and communicates at its gas inlet end 34A with the gas outlet 32 of the com- I bustion chamber and at its discharge end 34B-with-the inlet of a circularmetal conduit 36 extending through i the circumferential wall of the vessel 26 in sealing re1a-,

tion therewithand having its outlet endconnected. to the intake of the gas turbine 12, The outer wall of-the gas V V While the fluidheating 1 unit construction illustrated and hereinafter described is specifically designed and particularly adapted for natural the upper and of the gas pass 34 and adjacent pairs of these tubes have their discharge ends connected to-th'e outer periphery of the header 42 as one by bifurcated tubular portions 69D to provide adequate header ligament efliciencies. Of the remaining tubes 69 in the outer wall of the gas pass 34, half are bent radially, inwardly and horizontally at the top of the outer wall of the gas pass 34 to form with the metallic webs therebetween a portion of the upper end of the gas pass 34 and have their discharge ends directly connected to the outer periphery of the header 42; and the other half are bent radially inwardly and upwardly in spaced relation'to provide a screen 73 subjacent the header 42' extending between the ends of but not including the tube bank 40, forthe' protection of the header 42 from the high temperature heating gases, with half of these tubes having their discharge ends directly connected to the bottom of the header 42 the inner periphery of the header 42.

An upright radially extending baflle 74 comprising upwardly extending fluid heating tubes 75 having their intertube spaces closed by metallic webs is disposed (between and connected to the combustion chamber 30 and the outer wall of the gas pass 34, extends between the upper and lower ends of the gas pass 34, terminates at its inner end at a position adjacent the gas outlet 32 and at its outer end at a location adjacent to and downstream gas-wise of the inlet to the conduit 36, and cooperates with the enclosing walls of the gas pass 34- to direct the gases flowing from the combustion chamber through the gas pass 34 to the conduit 36. The tubes 75 have their lower ends connected. to a horizontally arranged radially extending tubular header 76' disposed subjacent the lower end of the gas pass 34, their upper ends connected to the header 42, and pass through the lower end of the gas pass 34 in sealing relation therewith. The header 76 extends through bent portions of the tubes of the screen 70 and is supplied with liquid from the and the remaining tubes reversely bent and connected to drum 46 by tubes 77 extending through the vessel 26 in' sealing relation therewith. Upwardly extending widely spaced fluid heating tubes 78 arranged in a radially extending row across the gas pass 34 and between the screen '62 and the tube bank 48 provide a screen against the high temperature heating gases for the end of the header 44 first encountered by the gases. The tubes 78 have their upper ends connected to the header 42,their lower ends connected to a horizontally arranged radially extending tubular header 79 disposed subjacent the lower end of the gas pass, and pass through the lower end of the gas pass 34 in sealing relation therewith. The header 79 passes between suitably bent portions of the tubes of the screen 70 and is supplied with liquid from the drum 46 by tubes 80 extending through the vessel 26 in sealing relation therewith.

Combustion air is supplied by the compressor 10 at a pressure of about 83 p.s.i.a. and temperature of 460? F. through the airheater 14, which is preferably of the tubular type, to the vessel 26 at'about 650 F. by way of a conduit 81 having its discharge end registering with a circular flanged opening 82 formed in the circumferential wall of the vessel 26 at a location subjacent the lower end of the gas pass 34. While high pressure air flows through the opening 82 to the inlets 64, 65 of the combustion chamber 30, the spaces 38, 38A and 38B are maintainedby this air under a pressure 2-4 p.s.i. higher than the heating gas pressure at any point along its flow path, so that any leakage through the outer boundary walls of the gas pass 34 and the portions of the combustion chamber 30 beneath the lower end of the gas pass 34 and adjacent the upper end thereof is inward toward the gas flow path rather than outward to avoid the blasting of the hot gases on the walls of the vessel 26. Thus, the outward thrust of the heating gases on the inner side of the outer boundary walls of the gas pass 34 and on the inner "side of the boundary walls of the portions of the boundary walls, resulting in a 'diiferentialthrust or only a few pounds. The relatively smalldiiferential thrust on these gboundary wallscoupled with ,the circular-form thereof minimizes the need for lateral on these boundary walls'to prevent warping or buckling thereof; 1

"Each of the inlets 64,65 is occupied by a row of vertically spaced horizontally arrangedtubular natural 7 gas burners 83. The burners 83 extend through the vessel 26 in sealing relation therewith and between bent por-- tions of the tubes of the screen 70, have their discharge ends provided with suitable nozzles for dispersion of the gas, and are arranged so that the gas discharged therefrom enters the combustion chamber with the high pressure combustion air substantially tangentially to the involute curved portions of the circumferential wall of the combustion chamber. Fuel-air streams from the inlet 64 enter the combustion chamber with the same direction of rotation as the fuel-air streams from the inlets 65.

With the fuel and, air inlets arranged'as described,com'

bustion of the gaseous fuel progresses at a high rate and the high velocity of the burning fuel and air causes.

the gas stream to follow a whirling path of travel upwardly through the combustion chamber before passing through the outlet 32 and overthe screen 62 to the gas inlet 34A of the gas pass 34. The baffle 74 cooperates with the boundary walls of the gas pass .34 to direct' the gases entering the inlet 34A in a substantially arcuate path of travel through the gaspass 34'and'consecutively over the screen tubes 78, the tube bank 40 and the super heater 52 positioned therein. From the superheater 52 35' the gases discharge to the outlet 34B, and thence pass over the tube portions 69D and throughthe'contduit 36 I to the" gas turbine 12. Gases dischargeffrom thejgas turbine 12 at a temperature of about 840 F., then flow the economizer 24 to the stack.

over the airheater 14 and j at a temperature of around 300 F.

Feedwa-ter at a pressure of about 1400 p.s.i.a's supplied by a feed pump, not shown, through feedwater heaters,

not shown, using steam bled from theturbine 18. partially heated 'feedwater then passes through" the economizer 24 and a conduit 84 to the drum 46..

Steam and water mixtures generated in the tubes of the tube bank 40, the screens62 and 78 and the boundary"- walls of the combustion chamber 30 and gas pass 34 discharge to the drum 46. Saturated steam is supplied from the drum 46 to the superheater inlet header 54 bytubular conduitSS, the steam then passing through thej tubes of the superheater 52, the superheater outlet header the steam turbine 18 for ex} 56 and the conduit 57 to pansion therein.

While in accordance with the provisions of the statutes I have illustrated and described herein the best form of the invention known to me, those skilled in the art will understand that changes may be made without departing from the spirit of the invention covered by my claimsg.

and that certain features of my invention may sometimes be used to advantage without a corresponding use, of

other features. 7

What is claimed is:

1. A fluid heating unit comprising walls defininganupright vessel, walls including fluid heating tubes defining an upright combustion chamber disposed longitudinally and in the central portion of said vessel, wall means ineluding fluid heating tubes disposed between said vessel and combustion chamber and coperating with said com bustion chamber to define a gaspass therebetween and with said vessel. to define a space'therebetween for air under pressure extending throughout substantially the V entire periphery of said gas pass, a fluid heating tube in 'saidgas pass, means fori'introducing fuel andair said combustion chamber substantially 'tangentally to p steel supports circumferential wall thereof and eifectinga whirlingpath of travel thereinlalo ng the, circumferential; wall, while' maintaining amair pressure throughout said space at least equaltol the gas pressure in said combustion chamher, a gas outlet from said combustion chamber opening means having substantially. its entire extent exposed to the heating gases as they discharge from said combustion chamber and being arranged to direct the gases flowing from said combustion chamber through said gas pass and over the tube bank therein to said gas exit;

2 A fluid: heating unit comprising walls defining an upright vessel, walls including fluid heating tubes defining an upright combustion chamber disposed longitudinally and in the central portion of said vessel, wall means including fluid heating tubes disposed between said vessel and combustion chamber and cooperating with said combustion chamber to define a gas pass therebctween extending along only a portion of the length of said combustion chamber and with said vessel to define a space therebetween for air under pressure extending throughout substantially the entire peripheryof said gas pass, a fluid heating tube bank in said gas pass, means associated with another portion of the length of the combustion chamber for introducing fuel and air into said combustion chamben adjacent one end and sub stantially tangentially to the circumferential wall thereof and effecting a whirling pathof travel therein along the circumferential wall, while maintaining an air pressure throughout said space at least equal to the gas pressure in said combustion chamber,a gas outlet from said combustion chamber at a location in said combustion chamber between the opposite endthereofand the zone of fuel and air entry thereto andgopening tosaid gas pass at a position upstrearn gas-wise of said tube bank, means forming a gas exit through said wall means and vessel and opening to said gas pass at a position downstream gas-wise of said tube ba'nk, and baffle means disposed outsideof said combustion, chamberv and across said gas pass and extending between said gas outlet and said gas exit from a position adjacentsaid gas outletfto a position adjacent said gas exit, said'baffle means having substantially its. entire extent exposed tothe heating gases as they discharge from said combustion chamber and being arranged to direct the gases flowing from said combustion chamber through said gas pass and over the tube bank therein to said'gas exit;

3. A supercharged: fluid heating unit comprising walls definingan upright vessel, walls including fluid heating tubes defining an upright combustion chamberof substantially circular cross-section disposed longitudinally and in the, central portion of said vessel, wall means including fluid heating tubes-disposed between said vessel and combustion chamber and cooperating with said cornbustion chamber to define an upwardly elongated gas pass therebetween extending along only a portion of the lengthof "said combustion. chamber and with said vessel to define an upwardly elongated space therebetween for air under pressure extendingthroughout substantially the entire periphery of said gas pass, a fluid heating tube bank in said gas pass, means associated with another portion of the length of the combustion chamber for introducing fuel, and air into said combustion chamber substantially, tangentially to the circumferential wall thereof and effecting a-whirling path of traveltherein along-the circumferential wall, while maintaining an air pressure throughout saidispace at least equal to the gas pressure in said combustion'chamber, said last named means including an axially elongated fuel and air inlet adjacent one end of; said, combustion chamber arranged substantially: tangentiallyuo the circumferential wall thereofpan, axially elongated gasroutlet in the circumferentialiwallof said combustion chamber at a location in said combustion chamber between the opposite end,

thereof and said fuel and air inlet and opening to said gas pass at a positionupstream gas-wise of said tube bank,

means-forming a, gas exit throughsaid wallmeans and vessel and openingto saidgaspass at a position downstreamgaswise of said tube banlc, and battle meansin said gas pasgexifi lding transversely and along the; height thereof and between saidv gas outlet and said gas exit from a position-adjacent said gasoutlet to a position adjacent said gasexit, said baffle meansv being disposed outside of said combustion chamber and having substantially its entire; extent exposedto the heating; gases as they discharge from said combustion chamber and being ar-- ranged to direct the gases flowing from said combustion chamber through; said gas pass and over the tube bank therein to said gas exit. I

4'. A vapor generating unit having a fluid circulation system and comprising walls defining an upright vessel, walls including upwardly extending vapor generating tubes defining an upright substantially cylindrical combustion chamber disposed concentrically within said vessel, wall means including upwardly extending vapor generating tubes disposed: between said vessel and combustion chamber and cooperating with said combustion chamber to define an upwardly elongated gas pass there, between extending along only a portion of the length of said combustion chamber and with said vessel to define anupwardly elongated space therebetween for air under pressure extending throughout substantialiy the entire peripheryof said gas pass, a vapor generating tube bank insaid gas pass disposed across the flow of gases therein, disposed across the flow a superheater in said gas pass of gases therein and connected for fluid fiow from the vapor generating tubes; means associated with another portion ofthe lengtlrof the combustion chamber for introducing fueland air into said combustionchamber and effecting a whirling path of travel therein along the circumferential wall, while maintaining an air pressure throughout said space at least equal to the gas pressure in said combustion chamber, said last named means including an axially elongated fuel and air inlet adjacent one endof said combustion chamber arranged substantially tangentially to the circumferential wall thereof, an axially elongated gas outlet in the circumferential wall of said combustion chamber at a location in said combustion chamber between the opposite end thereof and said fuel and air inlet and-opening to one end of said gas pass, means forming a gas exit through pass, bafile means in said gas pass extending transversely and alongthe height thereof and between said gas outlet and said gas exit from a position adjacent said gas outlet to a position adjacent said gas exit, said baffle means being disposed outside of said combustion chamber and having substantially its entire extent exposed. to the heating gases as they discharge from said combustion chamber and beingarranged to direct the gases flowingfrom said combustion chamber through said gas pass and over the tube bank and superheater therein to said gas exit. and means for connecting the vapor generating tubes into the fluid circulation system.

5. A supercharged vapor generating unit having a fluid circulation system and comprising walls defining an up right vessel, Walls including upwardly extending vapor generating tubes defining an upwardly elongated substantially cylindrical combustion chamber disposed concentrically within said vessel, wall means including upwardly extending vapor generating tubes disposed between said vessel and combustion chamber and cooperating with said combustion chamber to define an up 7 said wall means, and vessel and opening to the opposite end of said gas estates wardly elongated gas pass therebet'ween extending along bustion chamber for introducing fuel and air into said combustionchamber' and eifccting a whirling path of a travel therein along the circumferential wall, while maintaining an air pressure throughout said space at least equal to the gas pressure in said combustion chamber, said last named means including an axially elongated fuel and air inlet adjacent'thelower end of said combustion chamber arranged substantially tangentially to an involute curved portion of the circumferential wall thereof, an axially elongated gas outlet in the circumferential wall of said combustion chamber at a location in said combustion chamber between the upper end thereof and said fuel and air inlet and opening to said gas pass at a position upstream gas-wise of said tube bank alongsubstantially the full height thereof, means forming a' gas exit through said wall means and vessel and opening to said'gas pass at a position downstream gas-wise of and adjacent to said superheater, baflle means in said gas pass extending transversely and along the height thereof and between said gas outlet and said gas exit from a position adjacent said gas outlet to a position adjacent said gas exit, said baflle means being disposed outside of said combustion chamber and'having substantially its entire extent exposed to theheatinggases asthey discharge from said cornbustionchamber and being arranged to direct the gases flowing'from saidcombustion chamber through said 'gaspass and over thetube'bank and super1,

heater therein to said gas exit, and means for connecting the vapor generating tubes into said fluid circulation system.# g

6. A fluid heating unit comprising walls defining an upright vessel of substantially circular cross-section, walls defining anupright vessel v I 7 section, walls including fluid heating tubes defining an upright combustion chamber said combustion chamber to define an upwardly elongated annular gas pass therebetween extending along only a portion of the length of said combustion chamber and with said vessel to define an'upwardly elongated annular space therebetween for 'air under pressure extending through out substantially the entireperiphery'of said gas pass, a

fluid-heating tube bank in said" gas pass disposed across the flow of gases therein, means associated with another portion of the length of the combustion chamber for introducing fuel and air into said combustion chamber and efiecting a whirling path of travel therein along the circumferential wall, while maintaining an air pressure throughout saidspace at least equal to the gas pressure in said combustion chamber, said last named means including an axially elongatedfuel and air inlet adjacent one end of said combustion chamber arranged substantially tangentially to the circumferential wall thereof, an axially elongated gas outlet in the circumferential wall of said combustion chamber at a location in said combustion chamber between the opposite end thereof and said fuel and air inlet and opening to said gas pass at a position upstream gas-wise of said tube bank, means :forming'a gas exit through saidwall means and vessel and opening tosaid gas-wise'of said tube bank, and baflle means in said gas pass extending tran'sversely and alongthe height thereof including fluid heating tubes' defining an upright combustion chamber of substantially circular cross-section disposed longitudinally and in thecentral portion of said vessel, wall means including fluid heating tubes disposed between said vessel and combustion chamber and cooperating with said combustion chamber to define an upwardly elongated gas pass thereb'etween-and with said Vessel to define an upwardly elongated space therebetween for air under pressure extending throughout substantially the'entire periphery of said gas pass, a fluid heating tube bank in said gas pass, means for introducing fuel and air into said combustion chamber substantially tangentially to the circumferential wallthereofandeffecting a whirling path of travel therein along-thecircumferential wall, while maintaining an air pressure throughout said space at least equal to the g'as'pressure in said combustion chamber, a gas outlet from said combustion chamber opening to said gas pass at a position upstream gas-wise of said tube bank, means forming a gas exit through said wall means and vessel and'opening to said gaspass at a position downstrearn'gas-wise of 1 said tube bank, and battle means disposed outside or" said combustion chamber and across said gas pass and extending between said gas outlet and said gas exit from a position adjacent said gas outlet toa position adjacent said gas exit, said baflie means having substantially its'entire" extent exposed to the heating gases'as they discharge from said combustion chamber and being arranged to 1 direct the'gases flowing from said combustion chamber and between said gas outlet and said gas exit from af position adjacent said said; gas exit, said baffle me'ans being disposed outside of I said combustio'n chamber and having substantially risen gases as they discharge" and being arranged to direct the 'gases'flowing from said combustion chamber? pass and'over'the'tube ba'nktherein to gas outlet to aposition adjacent tire extent'e xposed' to the heating from said combustion' cham ber through said' gas said gas exit.

8. A supercharged an upright-vessel of substantially within a said vessel, wall vessel and combustion chamber and cooperating with said; combustion chamber to define an upwardly elongated annular'gas pass therebetween extending along only *a portion of the length of said combustion chamber and with said vessel to'define an upwardly elongated annular space therebetween for air under pressure extending .1 throughout substantially the entire periphery of saidgas pass,-a vapor generating tube-bank insaidgas pass dis {1* posed acrossi the flow of ,gases' therein, a 'superheater through said gas pass and over the tube banktherein to said gas exit. v V I v 7- A supercharged fluid heating unit comprising walls in said gas pass disposed across the flow of gases therein and connected for fluid flow from'the vapor generating with another {portion of the length of the-combustion chamber for "introducingffuelu andrair into said combustion chamber and efiecting a tubes, means associated whirling path of travel therein along thetcircumferenti'al wall, while maintaining an air pressurethroughout said, space at least equal to the gas pressure'in said combustion chamber, said last named means including an axially,

elongated fuel and air inlet adjacent the lower end of said combustion chamber arranged substantially tangentially to an involute curved portionof the circumferential wall thereof, an axially elongated gas outlet in the circumferential wall of' said combustion ehamberj at a location in said combustion chamber'between 'thef upper end thereof and said fuel and arrmmmmopsn ing to one end of said gas pass, means forming a gas of substantially circular ere-se of substantially circular cross-section" disposed concentrically within said='vessel,' wall means including fluid heating tubes disposedbe'tween' said vessel and combustion chamber and cooperating with gas' pass at' a position downstream vapor generating unit having a fluid circulation system -and comprising' walls defining" circular cross-section, 1 walls including upwardly extending vapor generatingf tu-bes defining an upright combustion chamber of sub-'* stan-tially circularcross-section disposed concentrically 7 means including 'upwardly' extending vapor generating tubes disposed between said exit through said wall means and vessel and opening to the opposite-end of said gas pass, baf,fle means: in said gas pass extending transversely between said gas outlet and said gas exit from a position adjacent saidgas. outlet to a positionadjacent said gas exit, said bafile means being disposed, outside of said combustion chamber and, extent exposed to the heating gases as they discharge from said combustion chamber and being arranged to direct the gases flowing from said combustion chamber through said gas pass and over the tube bank and superheater therein to said gas exit, and means for connecting the vapor generating tubes into said fluid circulation system.

9. A supercharged vapor'generating unit having a fluid circulation system and'comprising walls defining an upright substantially cylindrical vessel, walls including'upwardly extending vapor generating tubes defining an upright substantially cylindrical combustion chamber disposed concentrically within saidvessel, wall; means in cluding upwardly extending vapor generating tubes disposed between said vessel and, combustion chamber and cooperating with said combustion chamber to define an upwardly elongated annular gas pass therebetween. ex tending along only a portion of; the length of saidcombustion, chamber and with said vessel to define an upwardly elongated annular space therebetween for air under pressure extending throughout substantially theentire periphery of said gaspass a vapor; generating tube,

bank in said gas pass disposed across the, flow of gases therein, a superheater in said; gas pass at; a position;

downstream gasswiseof said tube-bank, disposed across the flow ofigases therein and connected for fluid flow from the vapor generating tubes, means associated with another portion of the length-of the combustion chamber for introducing fuel and air into said combustion: chamber and effecting a whirling path of travel therein along the circumferential wall, while maintaining; an, air pressure throughout said space at least equal tothe gas pressure -in said combustion chamber, saidxlast named means including axially elongated circumferentially spaced fuel andair inlets adjacent the lower'endlof said combustion chamber arranged: substantially: tangentially. to the circumferential wall thereof, an axiallyelongated gas:out- -let in the circumferential; wall of said combustion chamber at a location; in saidcombustionchamber between the upper; end, thereof and, said; fuel and air inlets and opening to said gas pass at a position upstream gas-wise of said tube bank along substantially. the full height thereof; means forming-a gas: exit'through said wall means andvessel and opening to said gas pass at a position downstream gas-wise of andadjacent to said superheater, bafliemeans in said, gas pass extending transversely and along the heightthereof and between said gasoutlet and said gas exit'frorn-a' position adjacent said gas outlet to a position adjacent said; gas exit, said baflle means being disposed outsideof said cornbustionchamber and having substantially its entire extent exposed to i the heating gases astheydischarge fromgsaidcombustionf chamber and being'arrangedsto direct the gases flowing from said combustion chamber through said gaspassiand' over the tube bank and superheat'er therein'to said gas exit, and means forconnecting thevapor generatingtubes' into said fluid circulation system;

A supercharged vapor generating'unit having a natural circulation fluid circulation system and comprising a horizontally arranged vapor-liquid drum, walls defining an upright vessel of substantially circular crosssection disposed subjacent said drurnandarranged with its axis substantially vertical, walls, including'upwardly extending vapor generating, tubes defining an upright combustion chamber of substantially circular cross-see tion disposed concentrically within said vessel, wall means including upwardly extending vapor generating tubes dis,-

and alongithe height thereof and having substantially-its entireposed between said vessel and combustion chamber and cooperating with said ;combustion chamber to definean, upwardly elongated annular gas pass therebetween extend-- ing along only-a portion of the length of said combustion chamber and with saidvesscl to define an upwardly elongated annular space therebetween for air under pressure extending throughout substantially the entire periphery of said gas pass, a vapor generating tube bank in said gas pass disposed across the flow of gases therein, asuperheater in said gas pass disposed across the flow of, gases therein and connected for'fluid flow from the liquid and vapor drum, means associated with another portion of the length of the combustion chamber for introducing fuel and air into said combustion chamber and effecting a whirling path of travel therein along the circumferential wall, while maintaining an air pressure throughout said space at least equal to the gas pressure in said combustion chamber, said last named means including an axially elongated fuel and, air'inlet adjacent the lower outlet and said gas exit from a position adjacent: said gas outletto, a position adj'acentsaid gasexit; saidbaffle.

means being-disposed outside of said combustion chamber and having substantially'itsentire extent exposed to the heating gases as they discharge from said combustion chamber, and, being arranged'to direct the gases-flowing from said combustion chamber, through said gas pass and over the tube, banks 'and-superheater therein to said; gas exit,,and, means for connecting the vapor generating, tubes; into, said, fluidci-rculation system for fluid flow to and fromsaid drum.

11. A supercharged vapor generating unit havinga,

natural circulation fluid circulation system and. comprising a horizontally arrangedvapor-liquid drum, walls defining an upwardly elongated substantially cylindricaljvcs selw disposed subjacent saiddrum and arranged with its axissubstantially vertical, walls including upwardly extending vaporgenerating tubes defining an upwardly elongated substantially cylindrical combustion chamber disposed concentrically within saidvessel, 'wall means including upwardly extending vapor generating tubes disposed between said :vessel and combustion chamber and cooperating with said combustion chamber to define, an,

upwardly elongatedannular gas'pass therebetwecn extending alongonly a portion of the length of saidjcombustion chamber and'with'said vessel to define an upwardly elongated annular space therebetween for air under pressure extendingthroughout substantially the-entire periphery OfSfilCl gas pass, a'vapor, generating tube bank in said gas pass including radially spaced arc-shapedrows. of up wardly extending tubes disposed across the flow of gases! therein, a superheater in said gas pass at a position downstream gas-wise of said, tube bank and including multilooped upwardly extending tubes arranged in radially spaced arc-shaped platens disposed across the flow of gases therein and connected for fluid flow from the liquid and vapor drum, meansassociated with another portion of the length of the combustion chamber for introducing fuel, and air into said combustion chamber and effecting a whirling path of travel therein along the circumferential wall, while maintaining an air pressure throughout said space at least equal to the gas pressure in said combustion chamber, said last named means including axially elongated circumferentially spaced fuel and air inlets adjacent the lower end of said combustion chamber arranged substantially tangentially to involute curved POI tions of the circumferential wall thereof, an axially elongated gas outlet in the circumferential wall of said combustion chamber at a location in said combustion chamber between the upper end thereof and said fuel and air inlets and opening to said gas pass at a position upstream gas-wise of said tube bank along substantially the full height thereof, means forming a gas exit through said wall means and vessel and opening to said gas pass at a position downstream gas-wise of and adjacent to said superheater, baffle means in said gas pass extending transversely and along the height thereof and between said gas outlet and said gas exit from a position adjacent said gas outlet to a position adjacent said gas exit, said bafiie means being disposed outside of said combustion chamber and having substantially its entire extent exposed to the heating gases as they discharge from said combustion chamber and 14 being arranged to direct the gases flowing from said combustion chamber in a substantially arcuate path of travel through said gas pass and over the tube bank and super heater therein to said gas exit, and means for connecting the vapor generating tubes into said fluid circulation system for fluid flow to and from said dru-m.

References Cited in the file of this patent UNITED STATES PATENTS France Jan. 14, 1957 

